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Experimental pages for OSGeodata Mailing List on [https://geodata.osgeo.org/servlets/BrowseList?listName=geodata&by=date&paged=false OSGeo.org].
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== Overview ==
  
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== Goal ==
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These are experimental pages ([[OSGeodata Discovery|1]],[[OSGeodata metadata exchange model|2]],[[OSGeodata metadata exchange protocol|3]],[[OAI-PMH|4]]) originated from OSGeodata Mailing List on [https://geodata.osgeo.org/servlets/BrowseList?listName=geodata&by=date&paged=false OSGeo.org].
  
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Citation from Jo Walsh: "Managing metadata well is the key to making a repository of open geographic data really useful and re-usable. Creating metadata can be a dull chore. Part of the problem is over-focus on production, rather than consumption; on standards, rather than on usage. The Geodata Committee at OSGeo has been working on a "simplest useful thing" approach to geographic metadata...".
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Let's unleash geographic information through open access and dissemination of geographic data and (metadata) search appliances!
  
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== Comparison between WFS and OAI-PMH ==
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Allow to '''[[OSGeodata Discovery| discover geodata]]'''! Let's make metadata 'sexy' again.
  
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WFS:
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For the '''[[OSGeodata Discovery| discovery of geodata]]''' we need a
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* Short for 'Web Feature Service'
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* '''[[OSGeodataMetadataModel| Geographic metadata exchange model]]''' as well as a
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* Background: A de-facto standard in GIS world owned by OGC
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* '''[[OSGeodataMetadataProtocol| Geographic metadata exchange protocol]]''' (catalog service).  
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* Requests: GetCapabilities, DescribeFeatureType, GetFeature, Transaction, LockFeature
 
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* Query:
 
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** Standard query includes spatial constraints (but no temporal?)
 
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** Needs to be profiled
 
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* Availability and outreach of services, tools and (open source) software:
 
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** Open source software see [http://www.freegis.org freegis.org]
 
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* ...
 
  
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OAI-PMH:
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For '''documentation''' an internal geodata management model is needed. For the '''metadata metadata exchange model''' a proposal was made called  '''[http://wiki.osgeo.org/index.php/Geodata_Metadata_Requirements#Information_model_for_metadata_exchange Dublin Core lite for Geo (DClite4G)]'''.
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* OAI ist short for [http://en.wikipedia.org/wiki/Open_Archives_Initiative 'Open Archives Initiative'], PMH is short for 'Protocol for Metadata Harvesting'.
 
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* Background: Was initiated by libraries, universities, museums and galleries to 'open access' (OA) free online availability of digital content.
 
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* Requests: Identify, ListMetadataFormats, ListSets, ListIdentifiers, ListRecords, GetRecord.
 
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* Query:
 
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** Standard query includes temporal constraints (but no spatial).
 
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** Needs to be extended
 
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* Availability and outreach of services, tools and (open source) software:
 
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** Open source software see [http://www.openarchives.org/tools/tools.html OAI-PMH tools]
 
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** Gateways available from publishing files to others 
 
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** Google reads it as a Sitemaps file ([http://www.google.com/support/webmasters/bin/answer.py?answer=34655 how to submit]) and Internet Archive uses it among others.
 
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* ...
 
  
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Common:
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Remarks: '''Metadata''' is just data about data. There is nothing special regarding its modeling and encoding. Metadata according to metadata exchange model should be strictly free (LGPL?).
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* RESTful
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* Both can be profiled to respond an 'output content model' which has yet to be defined.
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== Pleadings for metadata (models) and adequate protocols ==
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* ''Managing metadata well is the key to making a repository of open geographic data really useful and re-usable. Creating metadata can be a dull chore. Part of the problem is over-focus on production, rather than consumption; on standards, rather than on usage. The Geodata Committee at OSGeo has been working on a "simplest useful thing" approach to geographic metadata...''. (Citation from Jo Walsh)
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* [http://www.digitalearth.com.au/2006/06/23/lightweight-web-resource-catalogue/ Blog 1] - "Leight Weight Web Resource Catalogue"
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* [http://geotips.blogspot.com/2006/02/more-simple-web-services-catalogues.html Blog 2] - More Simple Web Services Catalogues...", and
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* [http://www.kralidis.ca/blog/2006/08/04/geospatial-catalog-development-brewing/ Blog 3] - geospatial-catalog-development-brewing.
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* [http://home.badc.rl.ac.uk/lawrence/blog/all Bryan's Blog]: "To extend or not to extend ..." ("In practice, we can exchange any derivative of the ISO19139 profiles using OAI and store them in xml databases.").
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* Paper "Are Geospatial Catalogues Reaching their Goals?" from [http://www.agile2006.hu/papers/Larson_Siliceo_etal.pdf Larson et al.].
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== Building blocks for metadata management ==
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Building blocks are:
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# A geometadata '''management model''' (e.g. internal to each organisation)
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# '''Tools''' to manage the geometadata
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# A geometadata '''[[OSGeodata metadata exchange model| exchange model]]'''
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# An '''encoding''' of the geometadata exchange model (probably XML)
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# Geometadata '''[[OSGeodata metadata exchange protocol| exchange protocols]]''' (like [[OAI-PMH]], see [[OSGeodata_Discovery]])
  
 
== Weblinks ==
 
== Weblinks ==
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* OGC's CSW 2.0
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* OGC's WFS
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Information:
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* [http://www.openarchives.org/OAI/openarchivesprotocol.html OAI-PMH] - Open Archives Initiative Protocol for Metadata Harvesting 2.0
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* [http://wiki.osgeo.org/index.php/Geodata_Metadata_Requirements#Discovery Wiki at osgeo.org] for requirements
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* [https://geodata.osgeo.org/servlets/BrowseList?listName=geodata Geodata mailing list at osgeo.org] for discussions
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<!-- Kategorien und ev. Koordinaten -->
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[[Kategorie: Geodaten]] [[Kategorie: Metadaten]] [[Kategorie: English]]

Aktuelle Version vom 29. Oktober 2006, 12:15 Uhr

Overview

These are experimental pages (1,2,3,4) originated from OSGeodata Mailing List on OSGeo.org.

Let's unleash geographic information through open access and dissemination of geographic data and (metadata) search appliances!

Allow to discover geodata! Let's make metadata 'sexy' again.

For the discovery of geodata we need a

For documentation an internal geodata management model is needed. For the metadata metadata exchange model a proposal was made called Dublin Core lite for Geo (DClite4G).

Remarks: Metadata is just data about data. There is nothing special regarding its modeling and encoding. Metadata according to metadata exchange model should be strictly free (LGPL?).

Pleadings for metadata (models) and adequate protocols

  • Managing metadata well is the key to making a repository of open geographic data really useful and re-usable. Creating metadata can be a dull chore. Part of the problem is over-focus on production, rather than consumption; on standards, rather than on usage. The Geodata Committee at OSGeo has been working on a "simplest useful thing" approach to geographic metadata.... (Citation from Jo Walsh)
  • Blog 1 - "Leight Weight Web Resource Catalogue"
  • Blog 2 - More Simple Web Services Catalogues...", and
  • Blog 3 - geospatial-catalog-development-brewing.
  • Bryan's Blog: "To extend or not to extend ..." ("In practice, we can exchange any derivative of the ISO19139 profiles using OAI and store them in xml databases.").
  • Paper "Are Geospatial Catalogues Reaching their Goals?" from Larson et al..

Building blocks for metadata management

Building blocks are:

  1. A geometadata management model (e.g. internal to each organisation)
  2. Tools to manage the geometadata
  3. A geometadata exchange model
  4. An encoding of the geometadata exchange model (probably XML)
  5. Geometadata exchange protocols (like OAI-PMH, see OSGeodata_Discovery)

Weblinks

Information:

Von «https://giswiki.hsr.ch/index.php?title=OSGeodata&oldid=3964»